The MX Immersion Circulator should only be mounted to tanks with a working depth of 7.25" (18.4 cm) or more. It clamps securely to both straight and curved tank walls.The following link provides additional information from the instruction manual or original manufacturer's brochure. Right-click to open the PDF in a new window or download it: http://www.labequip.com/stock/pictures/n1120.pdf